Method of making a hydroprocessing catalyst with a single step metal and chelant incorporation, the catalyst, and the use of the catalyst

ABSTRACT

A hydroprocessing catalyst composition that comprises a metal-incorporated support having incorporated therein a metal component and a chelating agent, and, further comprising a polar additive. The catalyst composition is prepared by incorporating in a single step at least one metal component and a chelating agent into a support material to form a metal-incorporated support followed by drying the metal-incorporated support and thereafter incorporating therein a polar additive.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/373,457 filed Aug. 13, 2010, the entire disclosure of which is herebyincorporated by reference.

FIELD OF THE INVENTION

The invention relates to a hydroprocessing catalyst composition thatincludes a metal-containing support having incorporated therein a metalcomponent and a chelant and further loaded with a polar additive and amethod of making and use of such a catalyst.

BACKGROUND OF THE INVENTION

With the increasingly more stringent requirements for reducing thelevels of sulfur and nitrogen contained in petroleum derived hydrocarbonproduct streams there has been an ongoing effort to find new or improvedhydroprocessing catalyst formulations and products that may suitably beused to more economically provide for the required sulfur and nitrogenreductions in the hydroprocessing of such petroleum derived hydrocarbonstreams.

Typical hydroprocessing catalysts known in the art can include a GroupVI metal (Mo and/or W) and a Group VIII (Co and/or Ni) as activecomponents which are supported on an inorganic oxide support material.These catalyst components may be combined and treated in a manydifferent ways to give catalyst compositions having certain desiredproperties.

One example of a hydrotreating catalyst proposed for use in thehydrodesulfurization, hydrodenitrogenation, and hydrodemetallization ofvarious petroleum fractions is disclosed in U.S. Pat. No. 7,235,173.This patent discloses a hydrotreating catalyst containing a group VIBand/or a group VIII with an organic compound as an additive. The organicadditive is a compound that contains at least one nitrogen atom andcorresponds to a specifically defined generic formula. The catalyst ofthe '173 patent is prepared by incorporating the hydrogenation metalsinto a matrix material, such as by ion exchange or dry impregnation ofthe substrate followed by a calcination. The organic compound may beintroduced into the catalyst composition by dry impregnation or byco-impregnation simultaneously with the metals or it may be present inthe sulfurization feedstock. The '173 patent indicates that itscatalysts that employ the particular organic additive exhibit improvedactivity over the comparative catalysts that do not employ an additive.

In U.S. Publication US 2009/0298677 is disclosed a hydroprocessingcatalyst that includes a carrier containing catalytically active metalsfrom Group VIB and Group VIII of the periodic table and a chelatingcompound. The chelating agents that are suitable for use in thehydroprocessing catalyst are preferably hydroxycarboxylic acid,especially those that contain one or more carboxyl groups and one ormore hydroxyl groups. One preferred chelating agent is citric acid. Thehydroprocessing catalyst is prepared by contacting a carrier with animpregnation solution of catalytically active metals and a chelatingagent followed by heating the impregnated carrier to provide a catalysthaving a loss on ignition that is within a desired range. The heatingtemperature is to be less than a temperature that would result insignificant or substantial degradation of the organic chelating agent.

As is indicated in these patents, there is an ongoing need to find newand improved hydroprocessing catalyst compositions that have improvedcatalytic properties. There is a need to find hydrotreating catalystcompositions that are highly active and stable when used in thetreatment of petroleum derived hydrocarbon process streams that havehigh concentrations of sulfur and nitrogen.

BRIEF SUMMARY OF THE INVENTION

Accordingly, provided is a hydroprocessing catalyst composition that maybe used in the hydroprocessing of hydrocarbon feedstocks to yield ahydrotreated hydrocarbon product. The hydroprocessing catalystcomposition comprises a metal-incorporated support having incorporatedtherein a metal component and a chelating agent, which further comprisesa polar additive. The inventive composition may be made by a method ofmaking a composition, wherein the method comprises: providing a shapedsupport; incorporating a solution, comprising a metal component and achelating agent, into the shaped support to provide a metal-incorporatedsupport; drying the metal-incorporated support so as to provide a driedmetal-incorporated support having a volatiles content in the range offrom 1 to 20 wt % LOI; and incorporating a polar additive into the driedmetal-incorporated support to thereby provide an additive impregnatedcomposition.

DETAILED DESCRIPTION OF THE INVENTION

The composition of the invention is particularly useful in applicationsinvolving the catalytic hydroprocessing of petroleum derived feedstocks,such as in the hydrotreating of atmospheric distillates, gas oils andresidues and of vacuum gas oils and residues. One embodiment of thecatalyst composition of the invention comprises a shaped support thathas incorporated therein, using a single step impregnation, a solutionof at least one metal component that provides a hydrogenation functionand a chelating agent to give a metal-incorporated support comprisingthe chelating agent and metal component that is dried and furtherincorporated with a polar additive to give an additive impregnatedcomposition.

The inventive composition has been found to have exceptionalhydrodesulfurization and hydrodenitrogenation activity and to exhibitgood catalytic stability when compared to other prior arthydroprocessing catalyst compositions. While it is not known withcertainty the actual mechanism that causes or brings about therecognized improvement in catalytic activity of the inventivecomposition, it is theorized that a combination of the use of thechelating agent with the polar additive provides for the observedcatalytic benefits.

When the chelating agent is used with the metal components of thecomposition it is believed that the chelating agent forms metal chelatecomplexes with the metals contained in the support and that thisreaction results in pulling the metals out or preventing them from beingstrongly bound to the surface of the support material. When thecomposition that has been treated with a chelating agent is furtherfilled with the polar additive, it is believed that the metal chelatecomplexes are dispersed over the surface of the support material. Thiscombined chelation treatment and use of polar additive is believed toprovide for enhanced catalytic performance.

The support used in the preparation of the inventive catalystcomposition may be any material that can suitably provide for thesupport of the metal hydrogenation components of the hydroprocessingcatalyst and which has porosity that may further be filled with thechelating agent and polar additive of the invention. A porous refractoryoxide is typically used as a support material. Examples of possiblesuitable porous refractory oxides include silica, alumina, titania,zirconia, silica-alumina, silica-titania, silica-zirconia,titania-alumina, zirconia-alumina, silica-titania and combinations oftwo or more thereof. The preferred porous refractory oxide for use inthe preparation of the support of the inventive composition is oneselected from the group consisting of alumina, silica, andsilica-alumina. Among these, the most preferred porous refractory oxideis alumina.

The porous refractory oxide generally may have an average pore diameterin the range of from about 50 Angstroms to about 200 Angstroms. Thetotal pore volume of the porous refractory oxide as measured by standardmercury porosimetry methods is in the range of from about 0.2 cc/gram toabout 2 cc/gram. The surface area of the porous refractory oxide, asmeasured by the B.E.T. method, generally exceeds about 100 m²/gram, andit is typically in the range of from about 100 to about 400 m²/gram.

The shaped support of the inventive catalyst composition may be preparedby any suitable method known to those skilled in the art. Typically, theporous refractory oxide starting material is in the form of a powder andis mixed with water, and, if desired or necessary, other chemical aidssuch as peptizing agents or flocculating agents or binders or othercompounds, to form a mixture or paste that may be formed into anagglomerate or shaped particle. It can be desirable to extrude themixture to form extrudates of any one or more of various shapes such ascylinders, trilobes, etc. having nominal sizes such as 1/16 inch, ⅛inch, 3/16 inch, and etc. The agglomerate or shaped particle thatcomprises one or more of the previously listed inorganic oxide compoundsis then dried and calcined to give the final shaped support particleused in the preparation of the inventive catalyst composition.

The shaped support particle is dried under standard drying conditionsthat can include a drying temperature in the range of from 50° C. to200° C., preferably, from 75° C. to 175° C., and more preferably, from90° C. to 150° C.

After drying, the shaped support particle is calcined under standardcalcination conditions that include a calcination temperature in therange of from 250° C. to 900° C., preferably, from 300° C. to 800° C.,and, most preferably, from 350° C. to 600° C.

The shaped support that has been calcined should have a surface area andpore volume that allow for the impregnation of the shaped support withthe metal components, chelating agent and polar additive of theinvention. The calcined shaped support can have a surface area(determined by the BET method employing N₂, ASTM test method D3037) thatis in the range of from 50 m²/g to 450 m²/g, preferably, from 75 m²/g to400 m²/g, and, most preferably, from 100 m²/g to 350 m²/g.

The mean pore diameter in angstroms (Å) of the calcined shaped supportis in the range of from 50 to 200, preferably, from 70 to 150, and, mostpreferably, from 75 to 125.

The pore volume of the calcined shaped support should exceed 0.55 cc/gand is typically in the range of from 0.5 cc/g to 1.1 cc/g. Moretypically, the pore volume is in the range of from 0.6 cc/g to 1.0 cc/g,and, most typically, it is from 0.7 to 0.9 cc/g. Less than ten percent(10%) of the total pore volume of the calcined shaped particle iscontained in the pores having a pore diameter greater than 350 Å,preferably, less than 7.5% of the total pore volume of the calcinedshaped particle is contained in the pores having a pore diameter greaterthan 350 Å, and, most preferably, less than 5%.

The references herein to pore size distribution and pore volume of thecalcined shaped particle are to those properties as determined bymercury intrusion porosimetry, ASTM test method D 4284. The measurementof the pore size distribution of the calcined shaped particle is by anysuitable measurement instrument using a contact angle of 140° with amercury surface tension of 474 dyne/cm at 25° C.

In a preferred embodiment of the invention, the shaped support, whichpreferably has been calcined, is impregnated with at least one metalcomponent and a chelating agent in a single step impregnation using asingle solution containing at least one metal salt, wherein the metalcompound of the metal salt solution is an active metal or active metalprecursor, and a chelating agent. One of the beneficial features of theinvention is that a single step impregnation of the metal component andthe chelating agent is used instead of using several steps to separatelyincorporate the metal components and the chelating agent into the shapedsupport.

The metal elements of the metal components are those selected from Group6 of the IUPAC Periodic Table of the elements (e.g., chromium (Cr),molybdenum (Mo), and tungsten (W)) and Groups 9 and 10 of the IUPACPeriodic Table of the Elements (e.g., cobalt (Co) and nickel (Ni)).Phosphorous (P) may also be a desired metal component.

For the Group 9 and 10 metals, the metal salts include Group 9 or 10metal acetates, formats, citrates, oxides, hydroxides, carbonates,nitrates, sulfates, and two or more thereof. The preferred metal saltsare metal nitrates, for example, such as nitrates of nickel or cobalt,or both. For the Group 6 metals, the metal salts include Group 6 metaloxides or sulfides. Preferred are salts containing the Group 6 metal andammonium ion, such as ammonium heptamolybdate and ammonium dimolybdate.

The concentration of the metal compounds in the impregnation solution isselected so as to provide the desired metal content in the finalcomposition of the invention taking into consideration the pore volumeof the support material into which the aqueous solution is to beimpregnated and the amounts of chelating agent and polar additive thatare to be incorporated into the support material that is loaded with themetal component. Typically, the concentration of metal compound in theimpregnation solution is in the range of from 0.01 to 100 moles perliter.

The amount of chelating agent in the impregnation solution is to providefor an amount of chelating agent in the range of from about 0.005 moleschelant to about 1 mole chelant per mole of active metal, i.e., Group 6,Group 9 and Group 10 metals described above, that is in the shapedsupport. It is more preferred for the impregnation solution to have anamount of chelating agent that is in the range of from 0.01 to 0.5 molesof chelating agent per mole of hydrogenation metal. Most preferred, theamount of chelating agent in the impregnation solution is in the rangeof from 0.05 to 0.1 moles of added chelant per mole of hydrogenationmetal.

The impregnation solution comprising the metal component and chelatingagent may further include a solvent that suitably provides for thedissolution of the chelating agent and metal compound. Possible solventsinclude water and alcohols, such as, methanol and ethanol, with waterbeing the preferred solvent for the chelating agent.

Any suitable means or method can be used in the impregnation of theshaped support with the single solution of chelating agent and metalcomponents; provided, that, such means or method provides for thesuitable incorporation or impregnation of the chelating agent and metalcomponent within the pores of the support material. Examples of suitablemethods of applying the solution to the shaped support can includedipping or spraying.

A preferred method for contacting the shaped support with the chelantand metal solution is by any suitable impregnation method known to thoseskilled in the art, for instance, impregnation by incipient wetnesswhereby the amount or volume of solution added to the shaped support issuch that the total volume of the added solution is in an amount thatmay range upwardly to about the available pore volume of the shapedsupport to be impregnated with the solution.

The metal content of the shaped support having a metal componentincorporated therein along with the chelating agent may depend upon theapplication for which the final polar additive impregnated compositionof the invention is to be used, but, generally, for hydroprocessingapplications, the Group 9 and 10 metal component, i.e., cobalt ornickel, preferably, nickel, can be present in the support material in anamount in the range of from 0.5 wt. % to 20 wt. %, preferably from 1 wt.% to 15 wt. %, and, most preferably, from 2 wt. % to 12 wt. %.

The Group 6 metal component, i.e., molybdenum or tungsten, preferably,molybdenum, can be incorporated into the shaped support in an amount inthe range of from 5 wt. % to 50 wt. %, preferably from 8 wt. % to 40 wt.%, and, most preferably, from 12 wt. % to 30 wt. %.

The above-referenced weight percents for the metal components are basedon the weight of the dry shaped support and the metal component as beingthe element regardless of the actual form, e.g., the oxide form orsulfide form, of the metal component.

Regardless of the actual means or method used to incorporate theimpregnation solution into the shaped support, the pores of theresulting metal-incorporated support will be filled with theimpregnation solution and, as a result, are unable to retain or befilled with any additional volume of liquid or other material. Themetal-incorporated support, thus, undergoes a drying step by which atleast a portion of the volatiles content is driven from themetal-incorporated support but leaving the metals and chelant behind inthe support material.

The removal of at least a portion of the volatiles from themetal-incorporated support opens up pore volume which may in a laterpreparation step be filled with the polar additive. Themetal-incorporated support, thus, is dried under drying conditions thatinclude a drying temperature that is less than a calcinationtemperature.

A significant feature of the invention is for the drying temperatureunder which the step of drying the metal-incorporated support isconducted not to exceed a calcination temperature. Thus, the dryingtemperature should not exceed 400° C., and, preferably, the dryingtemperature at which the metal-incorporated support is dried does notexceed 300° C., and, most preferably, the drying temperature does notexceed 250° C. It is understood that this drying step will, in general,be conducted at lower temperatures than the aforementioned temperatures,and, typically, the drying temperature will be conducted at atemperature in the range of from 60° C. to 150° C.

The drying of the metal-incorporated support is preferably controlled ina manner so as to provide the resulting dried metal-incorporated supportthat has a volatiles content in a particular range. The volatilescontent of the dried metal-incorporated support should be controlled sothat it does not exceed 20 wt. % LOI. It is preferred for the LOI of thedried metal-incorporated support to be in the range of from 1 wt. % to20 wt. % LOI, and, most preferred, from 3 wt. % to 15 wt. % LOI.

LOI, or loss on ignition, is defined as the percentage weight loss ofthe material after its exposure to air at a temperature of 482° C. for aperiod of two hours. LOI can be represented by the following formula:(sample weight before exposure less sample weight after exposure)multiplied by 100 and divided by (sample weight before exposure).

In the drying of the metal-incorporated support it is desirable toremove as little of the chelant therefrom as is practical and, thus,more than about 50 weight percent of the chelant that is incorporatedinto the metal-incorporated support, based on the total weight ofchelant incorporated into the metal-incorporated support, will remain inthe resulting dried metal-incorporated support. Preferably, the amountof chelant remaining on the dried metal-incorporated support exceeds 75weight percent, and, most preferably, more than 90 weight percent of thechelant originally added to the dried metal-incorporated support remainsin the dried metal-incorporated support when the polar additive issubsequently added. Thus, less than about 50 weight percent of thechelant originally added to the dried metal-incorporated support in thechelation treatment thereof should be removed from themetal-incorporated support during the drying step. Preferably, less than25 weight percent and, most preferably, less than 10 weight percent, ofthe chelant incorporated into the dried metal-incorporated support isremoved from the metal-incorporated support.

The chelating agent, or chelant, suitable for use in the inventivemethod includes those compounds that are capable of forming complexeswith the metal components, such as any of the Group 6 metals, Group 9metals and Group 10 metals, as described above, of the composition. Asearlier noted, it is particularly important to the inventive method thatthe chelant have properties which provide for the formation of chelatecomplexes with the metals of the composition in order to pull the metalsfrom the surface of its support material. The terms chelant, chelatingagent, and chelator are used herein to mean the same thing and areconsidered to be compound that functions as a ligand to form a chelateor chelate complex with a central metal ion.

Any chelant compound that suitably provides for the formation of metalchelant complexes as required by the inventive method described hereincan be used in the chelating treatment. Among these chelant compoundsare those chelating agents that contain at least one nitrogen atom thatcan serve as the electron donor atom for forming the complexes with themetals of the dried metal-incorporated support.

Examples of possible nitrogen atom containing chelating agents includethose compounds that can be classified as aminocarboxylic acids,polyamines, aminoalcohols, oximes, and polyethyleneimines.

Examples of aminocarboxylic acids include ethylenediaminetetraaceticacid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA),diethylenetriaminepentaacetic acid (DTPA), and nitrilotriacetic acid(NTA).

Examples of polyamines include ethylenediamine, diethylenetriamine,triethylenetetramine, and triaminotriethylamine.

Examples of aminoalcohols include triethanolamine (TEA) andN-hydroxyethylethylenediamine.

The preferred chelating agent for use in the inventive method is anaminocarboxylic acid that can be represented by the following formula:

Wherein R₁, R₂, R₃, R₄ and R₅ are each independently selected fromalkyl, alkenyl, and allyl with up to 10 carbon atoms and which may besubstituted with one or more groups selected from carbonyl, carboxyl,ester, ether, amino, or amide; wherein R6 and R7 are each independentlyselected from an alkylene group with up to 10 carbon atoms; wherein n iseither 0 or 1; and wherein one or more of the R₁, R₂, R₃, R₄ and R₅ hasthe formula:

Wherein, R₈ is an alkylene having from 1 to 4 carbon atoms; and whereinthe X is either hydrogen or another cation.

Preferred chelating agents include ethylenediaminetetraacetic acid(EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), anddiethylenetriaminepentaacetic acid (DTPA). The most preferred chelatingagent is DTPA.

The available pore volume of the pores of the dried metal-incorporatedsupport provided by drying of the metal-incorporated support may befilled with the polar additive of the invention. This is done byincorporating the polar additive into the dried metal-incorporatedsupport to provide an additive impregnated composition by using anysuitable method or means to impregnate the dried metal-incorporatedsupport with the polar additive.

The preferred method of impregnation of the dried metal-incorporatedsupport with the polar additive may be any standard well-known pore fillmethodology whereby the pore volume is filled by taking advantage ofcapillary action to draw the liquid into the pores of the dried chelanttreated metal-incorporated support. It is desirable to fill at least 75%of the available pore volume of the dried metal-incorporated supportwith the polar additive, and, preferably, at least 80% of the availablepore volume of the dried metal-incorporated support is filled with thepolar additive. Most preferably, at least 90% of the available porevolume of the dried metal-incorporated support is filled with the polaradditive.

In addition to the dispersing of metal complexes by the polar additive,it is also thought that the presence of the polar additive in theadditive impregnated composition, when it is placed in catalytic serviceor when it undergoes an activation in order to use the composition incatalytic service, provides certain benefits that help give a much moreactive catalyst than those of the prior art.

The polar additive that may be used in the preparation of the inventivecomposition can be any suitable molecule that provides for the benefitsand has the characteristic molecular polarity or molecular dipole momentand other properties, if applicable, as are described herein, and as aredisclosed in co-pending patent application U.S. application Ser. No.12/407,479, filed Mar. 19, 2009, (U.S. Publication No. US20100236988),which is incorporated herein by reference. Molecular polarity isunderstood in the art to be a result of non-uniform distribution ofpositive and negative charges of the atoms that make up a molecule. Thedipole moment of a molecule may be approximated as the vector sum of theindividual bond dipole moments, and it can be a calculated value.

One method of obtaining a calculated value for the dipole moment of amolecule, in general, includes determining by calculation the totalelectron density of the lowest energy conformation of the molecule byapplying and using gradient corrected density functional theory. Fromthe total electron density the corresponding electrostatic potential isderived and point charges are fitted to the corresponding nuclei. Withthe atomic positions and electrostatic point charges known, themolecular dipole moment can be calculated from a summation of theindividual atomic moments.

As the term is used in this description and in the claims, the “dipolemoment” of a given molecule is that as determined by calculation usingthe publicly available, under license, computer software program namedMaterials Studio, Revision 4.3.1, copyright 2008, Accerlys Software Inc.

Following below is a brief discussion of some of the technicalprinciples behind the computation method and application of theMaterials Studio computer software program for calculating moleculardipole moments.

The first step in the determination of the calculated value of thedipole moment of a molecule using the Materials Studio software involvesconstructing a molecular representation of the compound using thesketching tools within the visualizer module of Materials Studio. Thissketching process involves adding atoms to the sketcher window thatconstitute the compound and completing the bonds between these atoms tofulfill the recognized bonding connectivity that constitute thecompound. Using the clean icon within the Material Studio programautomatically orients the constructed compound into the correctorientation. For complex compounds, a conformational search is performedto ensure that the orientation used to calculate the molecular dipole isthe lowest energy conformation, i.e., it's natural state.

The quantum mechanical code DMo13 (Delley, B. J. Chem. Phys., 92, 508(1990)) is utilized to calculate the molecular dipole moments from firstprinciples by applying density functional theory. Density functionaltheory begins with a theorem by Hohenberg and Kohn (Hohenberg, P.; Kohn,W. “Inhomogeneous electron gas”, Phys. Rev. B, 136, 864-871 (1964);Levy, M. “Universal variational functionals of electron densities,first-order density matrices, and natural spin-orbitals and solution ofthe v-representability problem”, Proc. Natl. Acad. Sci. U.S.A, 76,6062-6065 (1979)), which states that all ground-state properties arefunctions of the charge density P. Specifically, the total energy E_(t)may be written as:E _(t) [ρ]=T[ρ]+U[ρ]+E _(xc)[ρ]  Eq.1where T[ρ] is the kinetic energy of a system of noninteracting particlesof density ρ, U [ρ] is the classical electrostatic energy due toCoulombic interactions, and E_(xc)[ρ] includes all many-bodycontributions to the total energy, in particular the exchange andcorrelation energies.

As in other molecular orbital methods (Roothaan, C. C. J. “Newdevelopments in molecular orbital theory”, Rev. Mod. Phys., 23, 69-89(1951); Slater, J. C. “Statistical exchange-correlation in theself-consistent field”, Adv. Quantum Chem., 6, 1-92 (1972); Dewar, M. J.S. J. Mol. Struct., 100, 41 (1983)), the wavefunction is taken to be anantisymmetrized product (Slater determinant) of one-particle functions,that is, molecular orbitals:Ψ=A(n)|φ₁(1)φ₂(2) . . . φ_(n)(n)|  Eq.2

The molecular orbitals also must be orthonormal:

φ_(i)|φ_(j)

=δ_(ij)  Eq.3

The charge density summed over all molecular orbitals is given by thesimple sum:

$\begin{matrix}{{\rho(r)} = {\sum\limits_{i}{{\phi_{i}(r)}}^{2}}} & {{Eq}.\mspace{14mu} 4}\end{matrix}$where the sum goes over all occupied molecular orbitals φ_(i). Thedensity obtained from this expression is also known as the chargedensity. From the wavefunctions and the charge density the energycomponents from Eq. 1 can be written (in atomic units) as:

$\begin{matrix}{T = \left\langle {\sum\limits_{i}^{n}{\phi_{i}{\frac{- \nabla^{2}}{2}}\phi_{i}}} \right\rangle} & {{Eq}.\mspace{14mu} 5}\end{matrix}$

In Eq. 6, Zα refers to the charge on nucleus α of an N-atom system.Further, in Eq. 6, the term ρ(r₁)V_(N), represents the electron-nucleusattraction, the term ρ(r₁)V_(e)(r₁)/2, represents the electron-electronrepulsion, and the term, V_(NN), represents the nucleus-nucleusrepulsion.

$\begin{matrix}\begin{matrix}{U = {{\sum\limits_{i}^{n}{\sum\limits_{\alpha}^{N}\left\langle {{\phi_{i}(r)}{\frac{- Z}{R_{\alpha} - r}}{\phi(r)}} \right\rangle}} +}} \\{{\frac{1}{2}{\sum\limits_{i}{\sum\limits_{j}\left\langle {{\phi_{i}\left( r_{1} \right)}{\phi_{j}\left( r_{2} \right)}\frac{1}{r_{1} - r_{2}}{\phi_{i}\left( r_{1} \right)}{\phi_{j}\left( r_{2} \right)}} \right\rangle}}} + {\sum\limits_{\alpha}^{N}{\sum\limits_{\beta < \alpha}\frac{Z_{\alpha}Z_{\beta}}{{R_{\alpha} - R_{\beta}}}}}} \\{= {{- {\overset{N}{\sum\limits_{\alpha}}\left\langle {{\rho\left( r_{1} \right)}\frac{Z_{\alpha}}{{R_{\alpha} - r_{1}}}} \right\rangle}} + {\frac{1}{2}\left\langle {{\rho\left( r_{1} \right)}{\rho\left( r_{2} \right)}\frac{1}{{r_{1} - r_{2}}}} \right\rangle} +}} \\{\sum\limits_{\alpha}^{N}{\sum\limits_{\beta < \alpha}\frac{Z_{\alpha}Z_{\beta}}{{R_{\alpha} - R_{\beta}}}}} \\{\equiv {\left\langle {{- {\rho\left( r_{1} \right)}}V_{N}} \right\rangle + \left\langle {{\rho\left( r_{1} \right)}\frac{V_{e}\left( r_{1} \right)}{2}} \right\rangle + V_{NN}}}\end{matrix} & {{Eq}.\mspace{14mu} 6}\end{matrix}$

The term, E_(xc)[ρ] in Eq. 1, the exchange-correlation energy, requiressome approximation for this method to be computationally tractable. Asimple and surprisingly good approximation is the local densityapproximation, which is based on the known exchange-correlation energyof the uniform electron gas. (Hedin, L.; Lundqvist, B. I. “Explicitlocal exchange correlation potentials”, J. Phys. C, 4, 2064-2083 (1971);Ceperley, D. M.; Alder, B. J. “Ground state of the electron gas by astochastic method”, Phys. Rev. Lett., 45, 566-569 (1980)). The localdensity approximation assumes that the charge density varies slowly onan atomic scale (i.e., each region of a molecule actually looks like auniform electron gas). The total exchange-correlation energy can beobtained by integrating the uniform electron gas result:ε_(xc)[ρ]≈∫ρ(r)ε_(xc)[ρ(r)]dr  Eq.7where E_(xc)[ρ] is the exchange-correlation energy per particle in auniform electron gas and ρ is the number of particles. In this work thegradient corrected exchange-correlation functional PW91 is used (Perdew,J. P.; Wang, Y. Phys. Rev. B, 45, 13244 (1992)).

With all the components derived to describe the total energy of anymolecular system within the density functional formalism, the dipolemoment can be calculated from a summation of the individual electronicand nuclear dipole moment vectors which are displayed at the end of theDMol3 output file.

References herein to the polar additive are understood to mean amolecule that has polarity and having a dipole moment, as calculated bythe aforementioned Materials Studio software or other known method thatwill provide substantially the same calculated value for the dipolemoment of a molecule as the Materials Studio software will provide,which exceeds the dipole moment of the hydrocarbon oil that is used inthe inventive composition.

The dipole moment of the polar additive should be at least or exceed0.45. However, it is preferred for the polar additive to have acharacteristic dipole moment that is at least or exceeds 0.5, and, morepreferred, the dipole moment of the polar additive should be at least orexceed 0.6. A typical upper limit to the dipole moment of the polaradditive is up to about 5, and, thus, the dipole moment of the polaradditive may be, for example, in the range of from 0.45 to 5. It ispreferred for the dipole moment of the polar additive to be in the rangeof from 0.5 to 4.5, and, more preferred, the dipole moment is to be inthe range of from 0.6 to 4.

As alluded to above, it is theorized that the polarity of the polaradditive is significant to the invention; because, the polarity isrequired for the interaction with the surface of the support materialand active metal components of the support material of the inventivecomposition. It is by these interactions that physical and chemicalbonds with the active phases of the inventive composition are formed.

A particularly desirable attribute of the polar additive is for it to bea heterocompound. A heterocompound is considered herein to be a moleculethat includes atoms in addition to carbon and hydrogen. These additionalatoms can include, for example, nitrogen or oxygen, or both. It isdesirable for the group of hetercompounds to exclude thoseheterocompounds that include sulfur, and, in all cases, the polaradditive does not include paraffin and olefin compounds, i.e. compoundsthat contain only carbon and hydrogen atoms. Considering the exclusionof sulfur-containing compounds from the definition of the group ofheterocompounds, it can further be desirable for the oil and additiveimpregnated composition, before its treatment with hydrogen and sulfur,to exclude the material presence of a sulfur-containing compound.

Specific polar compounds that may be suitable for use as the polaradditive of the invention are presented in the following Table 1, whichalso includes their calculated dipole moments.

TABLE 1 Polar Compounds and Their Calculated Dipole Moments BoilingCalc. Point Dipole Compound Formula Class (° C.) Moment 2,4-pentanedioneC₅H₈O₂ Diketone 140 1.59 Triethylphosphate C₆H₁₅O₄P Phosphate 215-2163.25 Triethylphosphite C₆H₁₅O₃P Phosphite 156 0.64 1-pentanol C₅H₁₂OAlcohol 138 1.85 Guanidine CH₅N₃ Imine n/a 3.8 Alanine C₃H₇NO₂ Aminoacid n/a 2.16 Glycine C₂H₅NO₂ Amino acid n/a 5.81 EthyleenediamineC₂H₈N₂ Diamine 116 2.46 Monoethanolamine C₂H₇NO Alcohol-amine 170 3.42Tetramethylurea C₅H₁₂N₂O Diamine 174-178 3.44 Acetonitrile C₂H₃N Nitrile82 3.87 n-methylpyrrolidone C₅H₉NO Cyclic-amide 202 3.92 glucose C₆H₁₂O₆sugar n/a 4.38 Sucrose C₁₂H₂₂O₁₁ sugar n/a 7.45 Octylamine C₈H₁₉N Amine175-176 1.36 Phenylboromic acid C₆H₇BO₂ Boric acid n/a 5.86n-etylcarbazole C₁₄H₁₃N Carbazole n/a 1.93 Acetophenone C₈H₈O ketone 2023.15 Diethyleneglycol C₄H₁₀O₃ Alcohol 244-245 2.76 Dibenzofuran C₁₂H₈OOxygen 285 0.78 heterocycle Dimethylformamide C₃H₇NO Amide 153 4.02Citric acid C₆H₈O₇ Carboxylic 175 3.37 Acid Ethylenediamine- C₁₀H₁₆N₂O₈Polyamino n/a 3.99 tetraacetic acid carboxylic acid Nitriltriacetic acidC₆H₉NO₆ Polyamino n/a 1.58 carboxylic acid

A preferred characteristic of the polar additive is for its boilingtemperature to be in the range of from 50° C. to 275° C. Morepreferably, the boiling temperature of the polar additive is to be inthe range of from 60° C. to 250° C., and, most preferably, it is in therange of from 80° C. to 225° C.

The most desirable compounds for use as the polar additive of theinvention are those selected from the group of amide compounds, whichincludes dimethylformamide.

The additive impregnated composition of the invention may be treated,either ex situ or in situ, with hydrogen and with a sulfur compound,and, indeed, it is one of the beneficial features of the invention thatit permits the shipping and delivery of a non-sulfurized composition toa reactor in which it can be activated, in situ, by a hydrogen treatmentstep followed by a sulfurization step. In the activation of the additiveimpregnated composition it first can undergo a hydrogen treatment thatis then followed with treatment with a sulfur compound.

The hydrogen treatment includes exposing the additive impregnatedcomposition to a gaseous atmosphere containing hydrogen at a temperatureranging upwardly to 250° C. Preferably, the additive impregnatedcomposition is exposed to the hydrogen gas at a hydrogen treatmenttemperature in the range of from 100° C. to 225° C., and, mostpreferably, the hydrogen treatment temperature is in the range of from125° C. to 200° C.

The partial pressure of the hydrogen of the gaseous atmosphere used inthe hydrogen treatment step generally can be in the range of from 1 barto 70 bar, preferably, from 1.5 bar to 55 bar, and, most preferably,from 2 bar to 35 bar. The additive impregnated composition is contactedwith the gaseous atmosphere at the aforementioned temperature andpressure conditions for a hydrogen treatment time period in the range offrom 0.1 hours to 100 hours, and, preferably, the hydrogen treatmenttime period is from 1 hour to 50 hours, and most preferably, from 2hours to 30 hours.

Sulfiding of the additive impregnated composition after it has beentreated with hydrogen can be done using any conventional method known tothose skilled in the art. Thus, the hydrogen treated additiveimpregnated composition can be contacted with a sulfur-containingcompound, which can be hydrogen sulfide or a compound that isdecomposable into hydrogen sulfide, under the contacting conditions ofthe invention. Examples of such decomposable compounds includemercaptans, CS₂, thiophenes, dimethyl sulfide (DMS), and dimethyldisulfide (DMDS). Also, preferably, the sulfiding is accomplished bycontacting the hydrogen treated composition, under suitablesulfurization treatment conditions, with a hydrocarbon feedstock thatcontains a concentration of a sulfur compound. The sulfur compound ofthe hydrocarbon feedstock can be an organic sulfur compound,particularly, one which is typically contained in petroleum distillatesthat are processed by hydrodesulfurization methods.

Suitable sulfurization treatment conditions are those which provide forthe conversion of the active metal components of the hydrogen treatedhydrocarbon oil and polar additive impregnated composition to theirsulfided form. Typically, the sulfiding temperature at which thehydrogen treated hydrocarbon oil and polar additive impregnatedcomposition is contacted with the sulfur compound is in the range offrom 150° C. to 450° C., preferably, from 175° C. to 425° C., and, mostpreferably, from 200° C. to 400° C.

When using a hydrocarbon feedstock that is to be hydrotreated using thecatalyst composition of the invention to sulfide the hydrogen treatedcomposition, the sulfurization conditions can be the same as the processconditions under which the hydrotreating is performed. The sulfidingpressure at which the hydrogen treated additive impregnated compositionis sulfided generally can be in the range of from 1 bar to 70 bar,preferably, from 1.5 bar to 55 bar, and, most preferably, from 2 bar to35 bar.

One of the benefits provided by the additive impregnated composition ofthe invention is that it can be utilized in a reactor system that isstarted up using a so-called delayed feed introduction procedure. In thedelayed feed introduction procedure, the reactor system, which includesa reactor vessel containing the additive impregnated composition, firstundergoes a heating step to raise the temperature of the reactor and theadditive impregnated composition contained therein in preparation forthe introduction of a sulfiding agent or heated hydrocarbon feedstockfor processing. This heating step includes introducing into the reactorthe hydrogen-containing gas at the aforementioned hydrogen treatmentconditions. After the hydrogen treatment of the additive impregnatedcomposition, it is thereafter treated with a sulfur compound in themanner as earlier described herein.

It has been found that the additive impregnated composition, afterundergoing the hydrogen treatment followed by treatment with a sulfurcompound, exhibits a greater catalytic hydrotreating activity of adistillate feedstock than do other similar, but non-impregnatedcompositions.

It is recognized that the additive impregnated composition of theinvention, after its treatment with hydrogen and sulfur, is a highlyeffective catalyst for use in the hydrotreating of hydrocarbonfeedstocks. This catalyst is particularly useful in applicationsinvolving the hydrodesulfurization or hydrodenitrogenation ofhydrocarbon feedstocks, and, especially, it has been found to be anexcellent catalyst for use in the hydrodesulfurization of distillatefeedstocks, in particular, diesel, to make an ultra-low sulfurdistillate product having a sulfur concentration of less than 15 ppmw,preferably, less than 10 ppmw, and, most preferably, less than 8 ppmw.

In the hydrotreating applications, the additive impregnated composition,preferably used in a delayed feed introduction procedure or otherwisetreated with hydrogen and sulfur, as described above, is contacted undersuitable hydrodesulfurization conditions with a hydrocarbon feedstockthat typically has a concentration of sulfur. The more typical andpreferred hydrocarbon feedstock is a petroleum middle distillate cuthaving a boiling temperature at atmospheric pressure in the range offrom 140° C. to 410° C. These temperatures are approximate initial andboiling temperatures of the middle distillate. Examples of refinerystreams intended to be included within the meaning of middle distillateinclude straight run distillate fuels boiling in the referenced boilingrange, such as, kerosene, jet fuel, light diesel oil, heating oil, heavydiesel oil, and the cracked distillates, such as FCC cycle oil, cokergas oil, and hydrocracker distillates. The preferred feedstock of theinventive distillate hydrodesulfurization process is a middle distillateboiling in the diesel boiling range of from about 140° C. to 400° C.

The sulfur concentration of the middle distillate feedstock can be ahigh concentration, for instance, being in the range upwardly to about 2weight percent of the distillate feedstock based on the weight ofelemental sulfur and the total weight of the distillate feedstockinclusive of the sulfur compounds. Typically, however, the distillatefeedstock of the inventive process has a sulfur concentration in therange of from 0.01 wt. % (100 ppmw) to 1.8 wt. % (18,000). But, moretypically, the sulfur concentration is in the range of from 0.1 wt. %(1000 ppmw) to 1.6 wt. % (16,000 ppmw), and, most typically, from 0.18wt. % (1800 ppmw) to 1.1 wt. % (11,000 ppmw). It is understood that thereferences herein to the sulfur content of the distillate feedstock areto those compounds that are normally found in a distillate feedstock orin the hydrodesulfurized distillate product and are chemical compoundsthat contain a sulfur atom and which generally include organosulfurcompounds.

The additive impregnated composition of the invention may be employed asa part of any suitable reactor system that provides for contacting it orits derivatives with the distillate feedstock under suitablehydrodesulfurization conditions that may include the presence ofhydrogen and an elevated total pressure and temperature. Such suitablereaction systems can include fixed catalyst bed systems, ebullatingcatalyst bed systems, slurried catalyst systems, and fluidized catalystbed systems. The preferred reactor system is that which includes a fixedbed of the inventive catalyst contained within a reactor vessel equippedwith a reactor feed inlet means, such as a feed nozzle, for introducingthe distillate feedstock into the reactor vessel, and a reactor effluentoutlet means, such as an effluent outlet nozzle, for withdrawing thereactor effluent or the treated hydrocarbon product or the ultra-lowsulfur distillate product from the reactor vessel.

The hydrodesulfurization process generally operates at ahydrodesulfurization reaction pressure in the range of from 689.5 kPa(100 psig) to 13,789 kPa (2000 psig), preferably from 1896 kPa (275psig) to 10,342 kPa (1500 psig), and, more preferably, from 2068.5 kPa(300 psig) to 8619 kPa (1250 psig).

The hydrodesulfurization reaction temperature is generally in the rangeof from 200° C. (392° F.) to 420° C. (788° F.), preferably, from 260° C.(500° F.) to 400° C. (752° F.), and, most preferably, from 320° C. (608°F.) to 380° C. (716° F.). It is recognized that one of the unexpectedfeatures of the use of the inventive additive impregnated composition ofthe invention is that it has a significantly higher catalytic activitythan certain other alternative catalyst compositions, and, thus, itwill, in general, provide for comparatively lower required processtemperatures for a given amount of hydtrotreatment of a feedstock.

The flow rate at which the distillate feedstock is charged to thereaction zone of the inventive process is generally such as to provide aliquid hourly space velocity (LHSV) in the range of from 0.01 hr⁻¹ to 10hr⁻¹. The term “liquid hourly space velocity”, as used herein, means thenumerical ratio of the rate at which the distillate feedstock is chargedto the reaction zone of the inventive process in volume per hour dividedby the volume of catalyst contained in the reaction zone to which thedistillate feedstock is charged. The preferred LHSV is in the range offrom 0.05 hr⁻¹ to 5 hr⁻¹, more preferably, from 0.1 hr⁻¹ to 3 hr⁻¹. and,most preferably, from 0.2 hr⁻¹ to 2 hr⁻¹.

It is preferred to charge hydrogen along with the distillate feedstockto the reaction zone of the inventive process. In this instance, thehydrogen is sometimes referred to as hydrogen treat gas. The hydrogentreat gas rate is the amount of hydrogen relative to the amount ofdistillate feedstock charged to the reaction zone and generally is inthe range upwardly to 1781 m³/m³ (10,000 SCF/bbl). It is preferred forthe treat gas rate to be in the range of from 89 m³/m³ (500 SCF/bbl) to1781 m³/m³ (10,000 SCF/bbl), more preferably, from 178 m³/m³ (1,000SCF/bbl) to 1602 m³/m³ (9,000 SCF/bbl), and, most preferably, from 356m³/m³ (2,000 SCF/bbl) to 1425 m³/m³ (8,000 SCF/bbl).

The desulfurized distillate product yielded from the process of theinvention has a low or reduced sulfur concentration relative to thedistillate feedstock. A particularly advantageous aspect of theinventive process is that it is capable of providing a deeplydesulfurized diesel product or an ultra-low sulfur diesel product. Asalready noted herein, the low sulfur distillate product can have asulfur concentration that is less than 50 ppmw or any of the other notedsulfur concentrations as described elsewhere herein (e.g., less than 15ppmw, or less than 10 ppmw, or less than 8 ppmw).

That which is claimed is:
 1. A method of making a composition, whereinsaid method consists essentially of the following steps: providing ashaped support; incorporating a solution, consisting essentially of ametal component at a concentration of said solution so as to provide thedesired metal content in the final composition and a chelating agent,into said shaped support to provide a metal-incorporated support; dryingsaid metal-incorporated support at a drying temperature not to exceed300° C. so as to provide a dried metal-incorporated support having avolatiles content in the range of from 1 to 20 wt % LOI thereby creatingan available pore volume; incorporating a polar additive without a metalcomponent into the available pore volume of said driedmetal-incorporated support in an amount sufficient to fill at least 75%of the available pore volume with said polar additive to thereby providean additive impregnated composition; treating said additive impregnatedcomposition by exposing said additive impregnated composition to agaseous atmosphere containing hydrogen at a hydrogen partial pressure inthe range of from 1 bar to 70 bar at a temperature ranging upwardly to250° C. and for a hydrogen treatment time period in the range of from0.1 hour to 100 hours to provide a hydrogen treated additive impregnatedcomposition; and sulfiding said hydrogen treated additive impregnatedcomposition to provide an activated additive impregnated composition. 2.A method as recited in claim 1, wherein said step of drying saidmetal-incorporated support is conducted at a drying temperature not toexceed 250° C.
 3. A method as recited in claim 1, wherein said chelatingagent is selected from the group of compounds consisting ofaminocarboxylic acids, polyamines, aminoalcohols, oximes, andpolyethyleneimines.
 4. A method as recited in claim 1, wherein saidpolar additive is a heterocompound having polarity and a dipole momentof at least 0.45.
 5. A method as recited in claim 1, wherein saidadditive impregnated composition comprises a Group 9 or Group 10 metalcomponent selected from the group consisting of cobalt and nickelpresent in an amount in the range of from 0.5 wt. % to 20 wt. %, and aGroup 6 metal component selected from the group consisting of molybdenumand tungsten present in an amount in the range of from 5 wt. % to 50 wt.%, wherein the weight percents are based on the weight of the drysupport material with the metal component as the element regardless ofits actual form.
 6. A method as recited in claim 1, wherein said shapedsupport comprises a porous refractory oxide selected from the group ofrefractory oxides consisting of silica, alumina, titania, zirconia,silica-alumina, silica-zirconia, titania-alumina, zirconia-alumina,silica-titania and combinations of two or more thereof; and wherein saidshaped support has a surface area (as determined by the BET method) inthe range of from 50 m²/g to 450 m²/g, a mean pore diameter in the rangeof from 50 to 200 angstroms (Å), and a total pore volume exceeding 0.55cc/g.
 7. A method as recited in claim 6, wherein at least 90% of theavailable pore volume of the pores of said dried metal-incorporatedsupport provided by drying of said metal-incorporated support is filledwith said polar additive.
 8. A method as recited in claim 1, whereindipole moment of the polar additive is in the range from 0.6 to 4.